How does one retrieve the TLE file without any internet access? For instance, I am out in the open sea without an internet connection for a few days. Can I still get the latest TLE file by some other means?
The TLE of what? And what for? Your question is lacking.
Without internet, you can:
- Have another form of contact (radio/cellular/carrier pigeon with USB stick/...)
- "Look up and see for yourself", Radar for example. Doesn't work for just any type of object, obviously, and will be hard to get precise data. Only really practical to confirm extrapolations of objects that are either close enough for active detection or big enough for passive detection
- Carry a big database and extrapolate